Understanding the Failure of the US Security Transfer during the Vietnam War

  • Published
  • By Jason Cooley


This article analyzes the unsuccessful transfer of control from US troops to the South Vietnamese Army during the Vietnam War between 1969 and 1975. It argues that a more thorough analysis of some factors is necessary to understand the transfer’s failure. Through this approach, the article shows that these determinants had the most impact on the outcome of the operation below the seventeenth parallel. By properly examining all relevant factors, the article aims to shed light on the conditions that often result in ineffective transfers in conventional conflicts.



The Vietnam War sparked intense scrutiny and extensive research, as scholars seek to understand its intricate dynamics and far-reaching implications. A focal point of investigation is the transfer of responsibility from US troops to the Army of the Republic of Vietnam (ARVN) during Richard Nixon’s presidency, as he aimed to bolster the ARVN’s capacity to counter North Vietnam’s aggression and maintain control over the southern region.1 Regrettably, the ultimate defeat of the South Vietnamese government has cast a shadow over this transfer, often deeming it as a failure.

Scholarly literature on the Vietnam War tends to attribute this unfavorable outcome to factors such as a scarcity of qualified commanders within the top echelons of the ARVN.2 While these determinants undeniably influenced events in Southeast Asia, it is crucial to acknowledge that the existing explanations are incomplete since they do not devote sufficient attention to other significant determinants highlighted in key primary and secondary sources. To rectify this oversight, this article will thoroughly examine the role of a short-term residual force and other factors closely linked to the US political climate, arguing that they exerted a more profound impact on the unfavorable outcome.

To gain a comprehensive understanding of the delegation of responsibility in security transfers, this article draws on the principal-agent theory from the field of economics. Unlike the commonly employed international relations theory of realism, the principal-agent theory offers a framework for analyzing how actors actively delegate responsibilities to others. Consequently, this article asserts that this theoretical perspective is better suited for comprehending the dynamics of security transfers and can provide valuable insights into the factors that contributed to the failure of the US security transfer in Vietnam.

Determinants That Contributed to the Unsuccessful Outcome in Vietnam

This section of the article strives to offer a comprehensive analysis of the determinants that played a role in the failure of the US security transfer in Vietnam. Each subsection will commence with a discussion on the approach employed to examine the specific determinant. While most subsections will focus on individual factors, one will devote attention to two determinants. Prior to presenting the analytical methods for these factors, it will be essential to provide an explanation for their collective examination.

Lack of Improvement in the South Vietnamese Officer Corps and Unconditional US Aid

After the initiation of the security transfer in Vietnam, the progress within the ARVN officer corps was notably lacking. The primary factor contributing to this undesirable outcome was the unconditional assistance provided by the United States. The connection between the shortage of competent South Vietnamese commanders and US aid necessitates their collective examination. By tracking the performances of key generals over time, readers can observe the lack of progress within the officer corps. Furthermore, analyzing the aid received by Saigon in 1972 will highlight the ineffectiveness of US assistance.

In the early 1970s, civilian officials in Saigon enlisted General Hoàng Xuân Lãm to lead a military operation in Laos. Since the North Vietnamese government had been using Laotian territory to supply military aid to personnel in South Vietnam, Lãm aimed to eliminate Hanoi’s main supply route during the mission.3 Initially, South Vietnamese soldiers managed to seize areas inside Laos, but the North Vietnamese forces eventually gained momentum and the South Vietnamese began to withdraw. Despite President Nguyn Văn Thiu’s attempt to present the initiative as a success, there were indications that such a label was unwarranted, including the continued movement of personnel and supplies down the northern portion of the Ho Chi Minh Trail. Sidney Berry, a brigadier general from the 101st Airborne Division, criticized Lãm’s planning as “of unacceptably low quality.”4

The poor performance of Lãm in the Laotian operation was not surprising since South Korean officers took similar imprudent steps during the early portion of the Korean War security transfer. However, when the South Korean officers participated in later engagements, they displayed the capacity for effective decision making on the battlefield. Lãm, on the other hand, did not improve over the course of time. Instead, as his conduct just before and during the 1972 Easter Offensive shows, he kept making choices that hindered his subordinates from defeating the enemy.5

General Nguyn Văn Toàn’s performance was also disappointing. During the conflict, Toàn held key positions within the ARVN hierarchy. At the time of the Easter Offensive, he was the commander of Military Region Two. The North Vietnamese attempted to gain control of various locations in this sector, including Kontum. However, the tactical maneuvers of the ARVN prevented the North Vietnamese from seizing Kontum. While high-ranking US officials wanted South Vietnamese commanders to play an integral part in the development of battle plans, Toàn did not devise the maneuvers for the campaign against the North Vietnamese. Instead, John Paul Vann, an assertive American advisor known for securing the responsibility of making decisions in pivotal situations, served as the lead tactician on the Kontum front in the Spring of 1972.6

After the successful defense of Kontum, Toàn became the head of South Vietnamese forces in Military Region Three. As fighting escalated in this sector in the first half of 1975, Toàn followed the action from his headquarters in Bien Hoa. During April, North Vietnamese territorial gains rose substantially within Toàn’s assigned region. This unfavorable turn of events did not prompt the South Vietnamese general to develop a new tactical plan to halt the North Vietnamese advance. Instead, he devoted most of his attention to arranging for passage from Bien Hoa to a more secure location.7

The shortage of competent commanders during the transfer raises questions about the methods used to alter the selection of South Vietnamese officers. The US officials overseeing the mission in South Vietnam had the option of threatening to withhold assistance until Thiu agreed to appoint more capable leaders. The amount of leverage in a partnership strongly influences whether a principal’s officials decide to use this pressure tactic. While the United States gave considerable aid to South Vietnam, it did not have operational control of ARVN personnel in the field.8 As a result, it was possible that the withholding of aid would lead to the alienation of the partner rather than the appointment of more proficient figures.

In addition to possessing a limited amount of leverage, the United States did not benefit from working with a formidable partner. While US leaders aimed to thwart acts of aggression by the North Vietnamese Army, Thiu wanted to prevent rogue elements within the military from removing him from power. To decrease the likelihood of a coup, he consistently appointed political loyalists who sought to use their prominent positions for personal gain.9 One can notice this corruption by examining the way that Toàn selected his subordinates. Within a military region, the leader needed to protect several provinces from communist attacks. Just below the leader in the chain of command, there were provincial chiefs who assisted with the defensive efforts. A former CIA analyst notes that Toàn filled the provincial posts in Military Region Three “on the basis of various personal gratuities.”10

The South Vietnamese regime also had to contend with a strong resistance movement. The National Liberation Front lost numerous fighters in the Tet Offensive toward the end of the 1960s. Although the Viet Cong could not consistently conduct attacks against ARVN personnel during the transfer years, it continued to attract support from citizens due to prevalent issues such as unfair elections south of the seventeenth parallel. The introduction of multiple reforms by the government could have reduced the appeal of the National Liberation Front in South Vietnamese society. However, Thiu and his advisors failed to take this step in the 1970s.11

The United States maintained an organization in South Vietnam to assist with the political struggle against the National Liberation Front. The members of Civil Operations and Revolutionary Development Support frequently assassinated and captured Viet Cong operatives in the Mekong Delta and other locations. They also allocated food and other vital supplies to citizens living in poor conditions. If Washington withheld this humanitarian assistance until more proficient leaders appeared in the ARVN, there was a chance that the beneficiaries of it would halt their support for the Thiu regime. The content in certain primary documents suggests that the fear of further weakening Thiu’s government played more of a role in the decision to refrain from using conditional aid to alter the leadership selection process in the ARVN than the issue of leverage. For instance, within one publication, a general notes how his superiors “believed that the South Vietnamese government fabric was fragile” and too much pressure “would be unduly risky.”12

The United States settled for trying to impact the filling of leadership posts with unconditional aid.13 When aid arrived in Saigon, Thiu had to consider a potential development on the domestic front. If he altered his selection method, it would become quite difficult for corrupt commanders to keep receiving the personal benefits associated with their respective positions. Consequently, Thiu could not rule out the possibility that aligning his behavior with US interests would prompt these officers to abandon him as others had deserted previous South Vietnamese leaders.14 To see how the internal principal possessed more leverage than the external one in this situation, it is necessary to focus on the aid that South Vietnam received in 1972.15 Although South Vietnam received more than a billion dollars in unconditional assistance from the United States during that year, Thiu’s behavior frequently benefited the contingent of unscrupulous and inept generals.16 Prior to the outbreak of the Easter Offensive, he could have instructed a capable individual to lead South Vietnamese forces in Military Region One. However, he decided to place Lãm, the commander who performed so poorly in the Laotian operation, in this key position. To the south, the North Vietnamese conducted attacks in Military Region Two as well. Therefore, it also would have been advantageous for Thiu to order a competent leader to oversee the defensive efforts in this sector rather than the unqualified Toàn.

The conditional aid promoted by prominent principal-agent theorists probably would have prompted the South Vietnamese regime to offer capable officers more opportunities to lead ARVN personnel in combat, as it yielded a positive outcome the only time that Washington utilized it during the war.17 Following Nixon’s inauguration, Henry Kissinger, the National Security Advisor, initiated peace talks with North Vietnamese officials in Paris. Despite Kissinger’s efforts, the North Vietnamese rejected various proposals for most of Nixon’s first term. However, toward the end of the term, Hanoi agreed to sign an agreement with the United States. Although the North Vietnamese accepted the deal, the South Vietnamese objected to many of its provisions, particularly the one that allowed North Vietnamese Army (NVA) personnel to remain south of the seventeenth parallel after the cease-fire. To persuade Thiu and his advisors to change their stance, the Nixon administration made it clear that US assistance would only continue if Saigon supported the agreement. After receiving this ultimatum from their principal, the South Vietnamese reluctantly agreed to back the deal.18

Once the initiative began, a few capable commanders emerged in key positions at the top of the ARVN. However, most South Vietnamese officers lacked the capacity to effectively execute their duties. The main factor that prevented the emergence of more competent leaders was the unconditional aid provided to Saigon by the United States. If US policy makers had attempted to influence the filling of vacancies with conditional aid, it is likely that qualified individuals would have led most of the South Vietnamese units.

Poor Training of South Vietnamese Soldiers

At the outset of the security transfer, South Vietnam lacked an effective training program for soldiers. US officials eventually introduced reforms designed to significantly improve the system. To see how this outcome did not surface, it will be necessary to closely examine the state of the program before and after the modifications.

During the initial year of the security transfer, the ARVN saw a significant rise in recruits.19 With the increase in the number of South Vietnamese soldiers, there was a need for more US advisors at training centers to provide instruction on crucial topics. However, US leaders did not send additional trainers to Southeast Asia. Even if more US advisors had been present, it is doubtful that most South Vietnamese personnel would have learned valuable lessons at training centers since evidence suggests the US Army primarily deployed unqualified personnel to the war zone in 1969. To succeed in a target country, an advisor must build a solid rapport with his advisees. Formidable relationships between training advisors and advisees were difficult to find below the seventeenth parallel for multiple reasons. Before their deployments, advisors completed a course at Fort Bragg, North Carolina, that provided them with information about the Vietnamese language.20 Since the course lasted only six weeks, the advisors arrived below the seventeenth parallel without fluency in the Vietnamese language. Over time, most advisors made no attempts to improve their understanding of the language. Consequently, many figures in the South Vietnamese Army perceived the Americans as arrogant.21 Conflicting perspectives on the appropriate timeframe for building an effective army further contributed to the divide between the advisors and advisees. The Americans often asserted that the effort to develop the ARVN should proceed rapidly, but this suggestion did not sit well with the South Vietnamese, who believed the campaign required ample time and patience.22

Upon leaving the training facilities, ARVN personnel received additional guidance from American field advisors. However, during the first year of the transfer, establishing strong relationships between American advisors and South Vietnamese soldiers proved challenging. The behavior of the Americans can be seen as a contributing factor to this issue. After all, many advisors in the field mirrored the actions of their counterparts at the training sites during their tours of duty. Nevertheless, an advisor in the field can compensate for showing insufficient respect for his advisees' language and timetable for improvement by taking specific measures during engagements. For instance, arranging for wounded soldiers to receive proper medical attention and calling in airstrikes at appropriate times can earn the respect of the advisees. Advisors may learn the importance of executing these maneuvers during clashes while completing multiple tours in such a role.23 However, it is essential for an advisor, as one analyst has noted, to possess a significant amount of combat experience as well. Many American field advisors in 1969, though, lacked any prior instructional experience and, as a result, did not fulfill this additional criterion for being an effective trainer due to their limited or nonexistent combat experience before arriving below the seventeenth parallel.24

The shortage of qualified American advisors was not the only problem associated with the instructional program. In 1969, US and South Vietnamese officials agreed to conduct joint operations in all military regions. While the missions in Military Region One were successful in helping ARVN personnel learn new techniques, the initiatives in other sectors failed to produce useful outcomes. Military Region Two provides a clear example of this. Effective coordination in joint operations requires participating armies to have headquarters in close proximity. However, the US and South Vietnamese headquarters in Military Region Two were not near each other, resulting in difficulties for US and ARVN commanders to work together on the battlefield.25 The coordination problem, along with other issues, led to the termination of joint missions before the South Vietnamese troops in Military Region Two could gain as much knowledge as their counterparts in Military Region One.

Due to concerning reports about the state of the training program in 1969, US policy makers decided to send Brig Gen General Donnelly Bolton, US Army, and a team of experts to Southeast Asia on a fact-finding mission. During the 1970 trip, the team of monitors uncovered valuable information by touring various training facilities and conducting interviews with relevant parties. For example, they discovered that the Military Assistance Command Vietnam (MACV) Training Directorate, responsible for supplying advisors to the ARVN’s training centers, was operating at 70 percent of its assigned strength.26 After Bolton reported these findings to civilian officials at the Pentagon, plans for implementing reforms began to take shape.

US military leaders in Vietnam had limited experience working with developing armies.27 They actively sought to improve training for ARVN personnel, though. One notable example is Gen Creighton Abrams, US Army, who, as the head of MACV, recognized the need for changes and took steps to influence his superiors. He sent recommendations to the Joint Chiefs of Staff, including the suggestion to dispatch additional advisors to Vietnam.28 As a result, by the end of 1971, more than 3,500 US instructors were working at training facilities south of the seventeenth parallel.29 However, their work ended when the peace agreement was signed at the start of 1973.

The US reform effort had another significant component aimed at improving the quality of instruction for ARVN personnel. To address the shortage of skilled trainers in South Vietnam, US officials made a concerted effort to send only proficient instructors to work with the ARVN, particularly those with combat experience. By June 1971, “over 90 percent of the training advisers were combat experienced.”30

Competent instructors serving in foreign countries cannot choose their assignments and must accept placements given to them by their superiors. When there is a shortage of administrators in the unit responsible for making assignments, though, it becomes challenging for trainers to receive suitable placements. Since the MACV Training Directorate faced this problem in the early 1970s, it would have been advantageous to dispatch capable administrators to South Vietnam to transform this entity, but individuals like Cornelius Ryan, the US Army General who transformed the Korean Military Advisory Group (KMAG) into a productive organization during the successful security transfer in the Korean War, were never sent to Southeast Asia. If the head of the mission in Vietnam possessed a different background, this turn of events probably would have taken place. James Van Fleet, one of the leaders of the US military mission on the Korean Peninsula, oversaw effective training initiatives in the past and recognized Ryan’s ability to alter the functioning of KMAG. However, lacking training experience to draw upon, Abrams did not know individuals with the capacity to change the way the MACV Training Directorate operated in South Vietnam.31

During the implementation of an initiative, one should anticipate success to emerge only half or the majority of the time.32 From 1972 to 1975, ARVN personnel failed to achieve objectives in half or the majority of their engagements. Consequently, it is necessary to conclude that the reforms in the South Vietnamese training program did not yield significant improvement. Given that US advisors departed before the end of the conflict, some may contend that it is unfair to apply such standards to the South Vietnamese effort. However, the success of a similar initiative to transform the South Korean training system from Spring 1951 suggests that progress is not contingent on the length of an advisory team’s mission. Within a little over a year of more-qualified advisors assisting South Korean soldiers, a robust program was already evident, culminating in an impressive Republic of Korea Army victory at White Horse Mountain.33

It is not appropriate to solely blame the United States for the failure to construct an effective soldier training system. After all, once a principal embarks on a reform campaign, it cannot implement changes without some cooperation from the leaders of the agent’s security forces. The primary goal of many commanders in the ARVN, as seen in the previous subsection, was not to improve the combat performance of their subordinates.34 As a result, when more US advisors arrived in the theater of operations during the early 1970s, there were few opportunities for them to work closely with officers to address the shortcomings of various units.

This subsection addressed the initiative to alter the training system for South Vietnamese troops. This campaign shared several connections with the effort intended to change the program for South Korean soldiers. However, it failed to generate as much improvement as its predecessor from the 1950s. This disappointing outcome can be attributed to the presence of a US commander who lacked experience in building forces in allied countries, the absence of effective leaders in the organization responsible for overseeing the activities of US advisors, and insufficient cooperation from South Vietnamese officers.

Troop Withdrawals

Certain decisions by both the United States and enemy nations ultimately determine the success or failure of most transfers. One crucial factor is how the United States withdraws combat troops from the target country. To avoid overwhelming the members of a fledgling force with new responsibilities, US policy makers must refrain from withdrawing personnel until there are signs of improvement. During his presidency, Nixon instructed his closest advisors to inform military officials in South Vietnam that a drawdown would only occur if ARVN personnel developed the capacity to perform the duties of US soldiers in an acceptable manner.35 In this subsection, the primary objective is to demonstrate how South Vietnamese improvement did not precede the drawdowns. By examining the main engagement that took place before a drawdown in 1969, it will be possible to observe the manner in which precipitous withdrawals unfolded. There will also be an opportunity to identify the key factor that prevented responsible withdrawals from occurring during Nixon’s presidency.

US leaders wanted to remove enemy personnel from a specific location in the forthcoming engagement. The initial phase of the analysis will establish that North Vietnamese soldiers fled from the area during the skirmish. The second part will then show how ARVN members did not play an integral part in the clearing operation. To demonstrate their failure to make a substantial contribution, it will be necessary to concentrate on tactical maneuvers and the extent of US involvement in the clash.

In the Summer of 1969, 25,000 troops were withdrawn from the theater of operations.36 During the spring, an offensive was launched to remove North Vietnamese troops from Ap Bia Mountain. After the initial assaults failed to dislodge the North Vietnamese from the top of Ap Bia, reinforcements arrived to participate in further attacks. The attacking forces encountered fierce resistance from the North Vietnamese during subsequent assaults. However, they eventually managed to reach the summit of Ap Bia on 20 May when the North Vietnamese retreated into Laos.37

A discussion about tactical maneuvers can illustrate how the South Vietnamese participants in the clash were not skillful. As Ap Bia contained routes that the enemy could use for a retreat, the ARVN needed to perform blocking maneuvers during the clash. However, the main account of the battle does not mention effective blocking maneuvers by the South Vietnamese. Instead, US monitors frequently refer to costly mistakes that prevented the First Division from achieving success in the early portion of the skirmish.38

It is now appropriate to discuss the extent of US involvement during the Battle of Ap Bia. When the ARVN’s First Division struggled in the initial part of the engagement, US officials went as far as to send the US 101st Airborne to Ap Bia. The members of this unit led the assault that prompted the North Vietnamese to abandon their defensive positions on 20 May. While this attack was impactful, it would be wrong to give the soldiers in the 101st Airborne all the credit for the North Vietnamese retreat. After all, as these soldiers fought on the ground, US pilots dropped a substantial number of bombs on NVA positions. The accounts of observers outside the US government show just how much damage this bombing campaign caused.39 Jay Sharbutt, a reporter for the Associated Press, noted that heavy jungles could be seen around Ap Bia at the beginning of the US aerial effort. By the time it ended, however, the mountain was almost bare.40

The preceding information demonstrates that the South Vietnamese Army did not make sufficient progress before drawdowns such as the one in the Summer of 1969. To identify the true cause of these withdrawals, it is necessary to concentrate on the US home front. While earlier works by Andrew Mack and others acknowledged how the political climate in the United States affected the handling of the conflict in Southeast Asia, they did not give enough attention to the specific ways in which the antiwar movement influenced events within the corridors of power in Washington, including discussions regarding the drawdowns.41 Toward the end of 1969, activists organized demonstrations in Washington and other major cities across the United States. The unrest continued in the Spring of 1970 after US and South Vietnamese personnel invaded Cambodia. This event prompted concerned students to lead protests at Kent State University in Ohio, Jackson State College in Mississippi, and other institutions of higher learning. Under mounting pressure from activists, Nixon had to withdraw US soldiers before ARVN personnel were fully prepared to take over their responsibilities. Former Chairman of the Joint Chiefs of Staff, Thomas Moorer, even states, “The reaction of the noisy radical groups was considered all the time. And it served to inhibit and restrict the decision makers.”42

This subsection, like the preceding one, presents evidence challenging the argument against direct monitoring.43 In the Spring of 1969, Department of Defense (DOD) officials chose to depend on US officers who observed the engagement to provide an accurate report on the behavior of South Vietnamese personnel. Although these Pentagon officials later reported to the White House that soldiers performed poorly against the NVA, Nixon still decided to withdraw US troops from the theater of operations in July and August. If it were not for the numerous demonstrations organized by the antiwar movement, Nixon might not have ordered this precipitous drawdown and subsequent ones during the transfer.

Short-Term US Residual Force

In addition to determining the appropriate timing for troop withdrawals, it is crucial for the principal to assess the agent’s capability to secure the entire country. If the principal concludes that the partner lacks the ability to act autonomously, it will either leave personnel behind to provide assistance or regain control of the security effort. When faced with a dilemma of control in South Vietnam, Nixon chose to support his ally in conducting the assigned task. This subsection will focus on the role of the residual force in the assistance campaign, examining developments before and after US personnel left to demonstrate how their rapid departure adversely affected the situation on the ground. While the primary goal is to highlight the significant impact of the residual force, time will also be taken to explain why Nixon elected to remove the unit from Southeast Asia so quickly.

At various junctures in the Vietnam withdrawal, US observers informed Nixon about South Vietnam’s inability to independently halt North Vietnam in combat. They further asserted the necessity of maintaining a residual force becomes discernible by considering a 1969 meeting between John Paul Vann and Richard Nixon at the White House. During the meeting, Vann apprised the president that the ARVN could effectively confront the NVA if it continued to receive air support from the United States.44 In light of this, the Nixon administration eventually decided to retain a contingent of US pilots in Southeast Asia.45

For years, US troops supplied data on the location of communist forces south of the seventeenth parallel to American aviators. However, by the early portion of 1973, ground troops were no longer present in South Vietnam. As a result, aviators had to rely on reports from ARVN personnel stationed on the frontlines.46 This collaboration between South Vietnamese soldiers and US pilots yielded positive results. Just days before the January cease-fire, the NVA launched attacks on over 400 villages and hamlets across South Vietnam, but the significant number of airstrikes conducted by US Air Force and US Navy pilots prevented the NVA from seizing control of these areas.47 Even after the cease-fire violation, US aviators continued to assist the South Vietnamese. In March, North Vietnamese forces captured Hong Ngu, a port on the Mekong River. However, US aviators conducted airstrikes near Hong Ngu, enabling the ARVN’s Ninth Division to retake the port.48

After the United States ended aerial support for the ARVN in the Summer of 1973, the North Vietnamese continued to launch attacks throughout South Vietnam. Between January and June, an additional 65,000 NVA soldiers arrived south of the seventeenth parallel, enabling the North Vietnamese to seize control of many targeted areas during the latter half of the year, including Le Minh, a ranger border camp located 25 miles west of Pleiku.49 Despite these territorial losses, the ARVN mounted counterattacks as 1974 began, retaking many of the areas lost in the second part of the previous year. Consequently, the US Defense Attaché Office reported to Washington that the South Vietnamese agent could effectively resist communist aggression without external assistance.50

The setbacks in early 1974 did not deter the NVA from launching further assaults later in the year, resulting in the capture of key outposts, villages, and other locations from the South Vietnamese. This loss of territory, coupled with the absence of robust counteroffensives, raised concerns among some US officials regarding the capabilities of the ARVN. However, there were still others who believed that the South Vietnamese could defeat the North Vietnamese without a residual force. Assistant Secretary of State Robert Ingersoll, for example, asserted before a Congressional committee that “South Vietnam is stronger militarily and politically than ever before.”51 It is reasonable to say that the skeptics within the US government had a better understanding of the ARVN’s abilities since the ARVN continued to lose territory during the NVA’s final offensive in the Spring of 1975.

To comprehend why the residual force ended its operations in Southeast Asia, despite the South Vietnamese being ill-prepared to face the North Vietnamese alone, it is necessary to focus solely on developments in the United States. Given how the input of Nixon’s subordinates played a crucial role in establishing the residual force, it is prudent to consider this factor in the current discussion. Various documents provide no evidence that the president’s advisors encouraged him to terminate the airstrikes in Southeast Asia. Instead, memorandums, memoirs, and other sources indicate that they hoped the bombing campaign would continue for an extended period. For instance, within his memoirs, Henry Kissinger states that he wanted the outcome of the conflict to “depend on whether the South Vietnamese, aided only by American airpower” could withstand North Vietnamese attacks.52

After ruling out the input of Nixon’s deputies as the cause of the decision to end the aerial campaign, attention must shift to the antiwar movement. Although antiwar critics were not as active in the mid-1970s, there is evidence that protests and other forms of collective political action still influenced the conduct of lawmakers in Washington. For example, in June of 1973, members of Congress approved a measure that prohibited US aerial operations across Indochina.53 With such Congressional restrictions, Nixon could not allow a residual force to contribute to the campaign against North Vietnam for an extended period.

While some theorists recommend that a principal take direct action upon discovering an underperforming agent, the United States addressed its dilemma of control in Southeast Asia by aiding its partner.54 The residual force present in the region helped the ARVN repel numerous NVA attacks. However, due to the continued influence of the antiwar movement on the home front, the president ordered the residual force to cease its activities after a brief period. When the ARVN fought without this support, it struggled to prevent NVA forces from taking control of crucial areas south of the seventeenth parallel.

Soviet Aid to North Vietnam

To understand the significant impact of enemy conduct on the outcome of a transfer, it is crucial to focus on the issue of supplies. In addition to providing a residual force, a principal must ensure that an underperforming agent leading the effort to prevent enemy aggression continues to receive an adequate amount of weapons and equipment. During the 1970s, there was a significant increase in military assistance from the Soviet Union to North Vietnam. As a result, policy makers in Washington needed to supply the ARVN with more weapons and equipment to counter NVA attacks. By examining the major offensive operations from 1972 and 1975, it will be possible to see that Washington failed to respond appropriately to the Soviet increase, leading to significant territorial gains by the NVA in South Vietnam. The following paragraphs will also provide an explanation for the US reaction.

Like Hanoi, Moscow aimed to spread communism throughout Indochina, with South Vietnam being their primary focus. In the Spring of 1972, North Vietnam faced a shortage of weapons and equipment due to limited domestic production capabilities. Without an increase in military supplies from the Soviet Union, the NVA would not have been able to mount assaults in Military Regions One, Two, and Three, where it faced sizable ARVN forces.55 To assist its ally, the Soviet Union sent a significant number of T-54 main battle tanks to North Vietnam, along with Soviet advisors providing training on their operation. NVA personnel later utilized these tanks against the ARVN, helping them take control of Quang Tri City and other key locations during the Easter Offensive.56

Following the Easter Offensive, Soviet aid to North Vietnam continued to escalate, surpassing the USD 1 billion mark in 1974.57 Without this substantial level of support, Hanoi would not have been able to launch the 1975 offensive that completed the takeover of South Vietnam. During this campaign, NVA forces frequently deployed the Soviet-made SA-2 high-altitude air defense system at the front lines. The use of these surface-to-air missiles forced South Vietnamese pilots to fly their planes at higher altitudes, making it challenging to target NVA strongholds during bombing campaigns.58

The increase in Soviet aid undoubtedly played a significant role in helping the NVA achieve numerous victories on the battlefield in 1975. However, it is important to note that a decrease in US aid also contributed to the NVA’s success.59 In 1974, when US assistance to South Vietnam fell to USD 813 million, many officials in the DOD predicted a decline in the performance of the ARVN.60 For instance, the head of the US Defense Attaché Office in Saigon warned that without sufficient aid “the South Vietnamese would lose, perhaps not right away but soon.”61 With fewer essential supplies arriving from the United States, South Vietnamese officials again faced the double principal dilemma. They could either try to appease the members of the ARVN by urging Washington to reverse its policy regarding supplies, or they could seek to please the United States by accepting the new policy and limiting the amount of weapons and equipment sent to the front. Initially, Saigon protested the reduction in aid, but South Vietnamese leaders eventually took steps to align with their external principal, including decreasing a soldier’s monthly bullet supply to 85 during the latter part of 1974.62 The inadequate supplies, combined with the aforementioned issues with officers and poor training, prevented the ARVN from effectively fighting in 1975.63

It is now appropriate to explain why the US government left their agent’s troops in such a vulnerable position. During the time of the aid cuts, Gerald Ford assumed control of the executive branch. It appears that he wanted to continue providing the South Vietnamese with enough assistance to prevent the NVA from seizing all the territory south of the seventeenth parallel. In March 1975, Frederick Weyand, the US Army Chief of Staff, conducted a comprehensive assessment of the situation in Southeast Asia during his visit to the theater of operations. Upon his return to Washington, he informed President Ford that the South Vietnamese could survive with USD 722 million in emergency aid from the United States.64 Ford then urged legislators to pass a bill that would provide Saigon with such emergency assistance.65

Regrettably, the South Vietnamese did not receive the necessary support, as there were no Congressional leaders in either party who shared Ford’s commitment to maintaining an adequate level of aid.66 To understand this reluctance to continue providing aid to Saigon, it is essential to consider the same factor that led to the precipitous withdrawal of troops and the brief presence of the residual force in the war zone. During the Spring of 1975, US Senators and Representatives vividly remembered the protests, sit-ins, and other demonstrations that occurred throughout the country earlier in the decade. Legislators like Congressman Don Bonker (D–WA) actively avoided working with the Ford administration, particularly in its efforts in Vietnam, to prevent reigniting such unrest. At one point, Bonker even stated, “People are drained. They want to bury the memory of Indochina. They regard it as a tragic chapter in American life, but they want no further part of it.”67

When faced with a dilemma of control in a security transfer, a principal cannot limit its response to leaving behind a residual force. Instead, it must also provide the underperforming agent with an adequate amount of supplies to carry out the majority of security responsibilities in the target country. In the case of South Vietnam, US officials failed to allocate sufficient weapons and equipment to the ARVN after the NVA received increased assistance from the Soviet Union, making it exceedingly difficult for the ARVN to defend significant areas south of the seventeenth parallel. If US policy makers did not have to contend with the possibility of reigniting the antiwar movement at home, they would likely have sent the necessary supplies to Southeast Asia.


This article examined the various factors that contributed to the unsuccessful security transfer in South Vietnam. The first part of the article focused on factors that have been highlighted in previous works. When a vacancy emerged at the top of the ARVN during the 1970s, the president of South Vietnam usually did not fill it with a qualified candidate since US policy makers attempted to influence his decision making with unconditional aid. Washington also aimed to upgrade the training system for ARVN personnel, but a comprehensive instructional program for troops did not materialize during the security transfer.

While the factors mentioned above certainly contributed to the failure in Southeast Asia, they were not as influential as the determinants that received inadequate attention in earlier studies. During a security transfer, it is crucial for US policy makers to prevent a nascent army from being overwhelmed by the responsibilities of US soldiers. This can be achieved by keeping troops in the target country until signs of improvement begin to emerge. In the early days of the mission in Vietnam, officials from the executive branch indicated that drawdowns would only occur after ARVN personnel had demonstrated proficiency in engagements against the enemy. However, hasty withdrawals were made to appease activists associated with the antiwar movement. If inexperienced service members are required to assume responsibilities too quickly, the United States can still salvage a security transfer by taking certain steps, including leaving a residual force in the war zone. Toward the end of the conflict in Vietnam, the White House kept a residual force in Southeast Asia to support the ARVN in fulfilling its responsibilities, but the unit could not remain in the region for a sufficient amount of time because lawmakers imposed restrictions on military operations overseas. It is also crucial to respond appropriately to supply changes in the enemy camp. As Soviet shipments to Hanoi significantly increased during the 1970s, South Vietnam required more weapons and equipment from the United States. When the US president attempted to gain support for such an increase, though, legislators refused to cooperate with him.

Besides identifying the factors that contributed to the unsuccessful outcome, the preceding material sheds light on the principal-agent partnerships that influence security transfers. After the commencement of the transfer, the United States initiated a direct monitoring campaign in Vietnam. In 1969, US monitors provided Washington with honest feedback regarding the behavior of ARVN personnel. Then, a year later, US observers provided accurate information about the conditions at South Vietnamese training facilities. Although some scholars suggest that a direct campaign is unlikely to keep a principal from encountering the problem of information asymmetry during a transfer, these situations indicate that this approach is effective.68

Following the establishment of a partnership, the behavior of the agent may not align with the interests of the principal. In such cases, the principal can offer conditional or unconditional incentives to influence the agent’s conduct. When Washington attempted to impact Saigon’s behavior with unconditional incentives, this approach failed to produce the desired outcome. Consequently, it is appropriate to conclude that this case further strengthens the popular contention that conditional incentives are more effective.69

When faced with an underperforming agent, a principal must decide whether to mount an assistance campaign or retake control of the security effort. In Vietnam, the United States decided to assist the agent in conducting the assigned task. As members of the US residual force briefly worked with ARVN personnel, NVA troops did not experience much success in combat. Therefore, if the residual force had remained active in the theater of operations for more than a year, and Washington continued to provide an adequate number of weapons and equipment to its agent, Hanoi probably would not have been able to conquer South Vietnam. The experience in South Vietnam suggests that, rather than resorting to direct action as recommended by Berman, Lake, Miquel, and Yared, a principal should consider assisting an underperforming agent when facing a dilemma of control in a security transfer.

An agent may encounter issues after the establishment of a partnership, including the prevalence of double principals. In 1972, when Saigon faced pressure on the foreign and domestic fronts, it made a decision that aligned with the interests of an internal principal. However, later in the decade, its actions aligned with the interests of an external principal. These reactions show that the leverage of an external principal strongly influences an agent’s behavior. Since aid was unlikely to be withheld in 1972, the government did not need to align its behavior with the objectives of the United States. As conditions deteriorated rapidly south of the seventeenth parallel and there were no other allies to ask for weapons and equipment in the mid-1970s, though, Saigon recognized the necessity of cooperating with Washington.

Jason Cooley

Mr. Cooley holds a master’s degree in political science from the University of Connecticut. He teaches courses on US politics at the University of Hartford and Tunxis Community College in Farmington, Connecticut. His research interests include transnational revolutionary organizations, US foreign policy, and covert actions.

Disclaimer: The views and opinions expressed or implied in the Journal of Indo-Pacific Affairs are those of the authors and should not be construed as carrying the official sanction of the Department of Defense, Department of the Air Force, Air Education and Training Command, Air University, or other agencies or departments of the US government or their international equivalents.


1 Throughout most of Lyndon Johnson’s presidency, US soldiers fought battles against the members of the Vietcong. After the ranks of this guerrilla organization were depleted in the 1968 Tet Offensive, though, Hanoi became more reliant on troops from the North Vietnamese Army. Consequently, as ARVN personnel started to assume American duties in 1969, they mainly participated in conventional engagements. For more information on the changing nature of the conflict, see Gregory Daddis’ Withdrawal: Reassessing America’s Final Years in Vietnam.

2 For more information on the lack of improvement in the South Vietnamese Officer Corps, see Caitlin Talmadge’s The Dictator’s Army and Jeffrey Clarke’s Advice and Support. The inadequate training program for South Vietnamese troops kept success from emerging during the transfer years as well. To learn more about the role which this determinant played in the unsuccessful outcome, read Robert D. Ramsey III, Advising Indigenous Forces: American Advisors in Korea, Vietnam, and El Salvador (Fort Leavenworth, KS: Comat Studies Institute Press, 2006) and James Collins, The Development and Training of the South Vietnamese Army, 1950–1972 (Washington: Government Printing Office, 2014). While these factors are discussed in the literature regarding the Vietnam conflict, they do not receive as much attention as the US political landscape. One of the most prominent studies about this determinant is Andrew Mack, “Why Big Nations Lose Small Wars: The Politics of Asymmetric Conflict,” World Politics 27, no. 2 (January 1975): 175–200.

3 H.R. Haldeman, Diary Entry, 22 December 1970.

4 General Sidney Berry, quoted in David Fulghum and Terrance Maitland, The Vietnam Experience: South Vietnam on Trial (Boston: Boston Publishing Company, 1984).

5 Colonel Harold Hawkins, Message to General Thomas Bowen, 3 February 1972.

6 Dale Andrade, America’s Last Vietnam Battle (Lawrence: University of Kansas Press, 2001), 313.

7 James Willbanks, Abandoning Vietnam (Lawrence: University of Kansas Press, 2004), 275.

8 Bruce Palmer, The 25-Year War: America’s Military Role in Vietnam (Lexington: University Press of Kentucky, 1984), 50.

9 Talmadge, The Dictator’s Army, 9.

10 Frank Snepp, Decent Interval: An Insider’s Account of Saigon’s Indecent End Told by the CIA’s Chief Strategy Analyst in Vietnam (New York: Random House, 1977), 193.

11 Andrew Wiest, Vietnam’s Forgotten Army: Heroism and Betrayal in the ARVN (New York: New York University Press, 2008), 302.

12 Palmer, The 25-Year War, 88.

13 Willbanks, Abandoning Vietnam, 173–75.

14 Neil Sheehan, A Bright Shining Lie (New York: Random House, 1988), 377.

15 Alexander Downes, Catastrophic Success: Why Foreign-Imposed Regime Change Goes Wrong (Ithaca: Cornell University Press, 2021), 6.

16 Jeffrey Clarke, Advice and Support: The Final Years, 1965-1973 (Washington: Center of Military History, 1988), 502.

17 Stephen Biddle, Julia MacDonald, and Ryan Baker, “Small Footprint, Small Payoff: The Military Effectiveness of Security Force Assistance,” Journal of Strategic Studies, 41, no. 2 (2017), 131; and Daniel Byman, “Friends Like These: Counterinsurgency and the War on Terrorism,” International Security 31, no. 2 (2006), 113.

18 Henry Kissinger, White House Years (Boston: Little, Brown, and Company, 1979), 1469.

19 Sheehan, A Bright Shining Lie, 732.

20 Wiest, Vietnam’s Forgotten Army, 86.

21 Ramsey, Advising Indigenous Forces, 44.

22 Wiest, Vietnam’s Forgotten Army, 87.

23 Wiest, Vietnam’s Forgotten Army, 84.

24 Clarke, Advice and Support, 317.

25 Willbanks, Abandoning Vietnam, 53.

26 Willbanks, Abandoning Vietnam, 37.

27 Kissinger, White House Years, 272–73.

28 Willbanks, Abandoning Vietnam, 37–38.

29 Cao Van Vien, Indochina Monographs: The U.S. Adviser (Washington: Center of Military History, 1980), 175.

30 Collins, The Development and Training of the South Vietnamese Army, 1950-1972, 105.

31 Kissinger, White House Years, 272–73.

32 Allan McConnell, “Policy Success, Policy Failure and Grey Areas in Between,” Journal of Public Policy 30, no. 3 (2010), 352.

33 United States Eighth Army, Command Report, 1952, Section One, Narrative.

34 Snepp, Decent Interval, 193.

35 General Earle Wheeler, Message to General Creighton Abrams, April 1969.

36 Nguyen Duy Hinh, Indochina Monographs: Vietnamization and the Cease-Fire (Washington: Center of Military History, 1980), 27.

37 Stanley Karnow, Vietnam: A History (New York: The Viking Press, 1983), 601.

38 US Military Assistance Command Vietnam, Combat After Action Report for the Battle of Ap Bia, 1970.

39 US Military Assistance Command Vietnam, Combat After Action Report for the Battle of Ap Bia.

40 Jay Sharbutt, “U.S. Assault on Viet Mountain Continues, Despite Heavy Toll,” The Washington Post, 20 May 1969.

41 See for example, Andrew Mack, “Why Big Nations Lose Small Wars: The Politics of Asymmetric Conflict,” World Politics 27, no. 2 (January 1975): 175–200.

42 Thomas Moorer, quoted in Gregory Daddis, Withdrawal: Reassessing America’s Final Years in Vietnam (Oxford: Oxford University Press, 2017).

43 Biddle, MacDonald, and Baker, “Small Footprint, Small Payoff,” 98.

44 Sheehan, A Bright Shining Lie, 735.

45 Palmer, The 25-Year War, 155.

46 Dong Van Khuyen, Indochina Monographs: RVNAF Logistics (Washington: Center of Military History, 1984), 387.

47 Robert Schulzinger, A Time for War (Oxford: Oxford University Press, 1997), 305.

48 Willbanks, Abandoning Vietnam, 191–92.

49 Alan Dawson, 55 Days: The Fall of South Vietnam (Englewood Cliffs, NJ: Prentice Hall, 1977), 99.

50 United States Defense Attaché Office in South Vietnam, RVNAF Quarterly Assessment, February 1974.

51 Robert Ingersoll, quoted in Arnold Isaacs, Without Honor: Defeat in Vietnam and Cambodia (Baltimore: John Hopkins University Press, 1983).

52 Kissinger, White House Years, 986.

53 Walter Isaacson, Kissinger (New York: Simon and Schuster, 2005), 487.

54 Eli Berman et al., “Principals, Agents, and Indirect Foreign Policies,” in Proxy Wars: Suppressing Violence Through Local Agents, ed. Eli Berman and David A. Lake (Ithaca, NY: Cornell University Press, 2019), 1–27.

55 Matthew J. Nanes, “Lebanon and Gaza, 1975–2017,” in Proxy Wars: Suppressing Violence through Local Agents, ed. Eli Berman and David A. Lake (Ithaca, NY: Cornell University Press, 2019), 110–36.

56 Snepp Decent Interval, 290.

57 Lam Quang Thi, Autopsy: The Death of South Vietnam (Phoenix: Sphinx Publishing, 1986), 141.

58 Snepp Decent Interval, 358.

59 Van Tien Dung, Our Great Spring Victory: An Account of the Liberation of South Vietnam (New York: Monthly Review Press, 1977), 197.

60 David Shriek, “South Vietnam, A U.S. Subsidiary,” New York Times, 27 January 1974.

61 United States Defense Attaché Office in South Vietnam, RVNAF Quarterly Assessment, July 1974.

62 William LeGro, Vietnam from Cease-Fire to Capitulation (Washington: Center of Military History, 1985), 86–87.

63 Dung, Our Great Spring Victory, 17.

64 General Frederick Weyand, Memorandum for President Gerald Ford, April 1975.

65 Snepp Decent Interval, 337.

66 Willbanks, Abandoning Vietnam, 261.

67 Congressman Don Bonker, quoted in James Willbanks, Abandoning Vietnam.

68 Biddle, MacDonald, and Baker, “Small Footprint, Small Payoff,” 98.

69 Biddle, MacDonald, and Baker, “Small Footprint, Small Payoff,” 131; and Byman, “Friends Like These,” 113.




The views and opinions expressed or implied in JIPA are those of the authors and should not be construed as carrying the official sanction of the Department of Defense, Department of the Air Force, Air Education and Training Command, Air University, or other agencies or departments of the US government or their international equivalents. See our Publication Ethics Statement.